Within seconds, seven of Peters' friends retweeted the message. One of them asked another South Africa member of the social network - @Pigspotter, who has more than 100,000 followers - to help spread the word.

Peter's friends ask for help

@Pigspotter specialises in identifying police roadblocks and many of his followers on the social network belong to the security forces.

The appeal created a real buzz and police patrols kept each other informed via Twitter.

The car was eventually located 150 miles from where it was hijacked, much to the relief of its occupant, who was uninjured though traumatised by the experience.

When the kidnappers encountered a roadblock, they abandoned their car and fled on foot.